1. Technical Field
The present invention relates to an atomic oscillator, and a frequency signal generation system.
2. Related Art
An atomic oscillator as a frequency signal generator is known that includes a light source; an atom cell charged with alkali metal atoms such as cesium; a photodetector for detecting light having passed through the atom cell; and a container housing the light source, the atom cell, and the photodetector. The atomic oscillator oscillates as a result of an energy transition of alkali metal atoms.
For example, JP-A-2015-119443 describes a gas cell having an internal space charged with metal atoms and a buffer gas. The buffer gas is a mixed gas of nitrogen gas and argon gas, and the molar fraction of the argon gas in the mixed gas is adjusted in a range of 15% to 40% to achieve desirable temperature characteristics.
However, when the atmosphere inside the container housing the atom cell is atmospheric air, there are cases where substances with small molecular weights, such as helium, enter the atom cell through it. This may cause fluctuations in the frequency of the atomic oscillator.